Paper-based laminated packaging has been the most conventional and widely practiced method to keep contents in such packaging fresh and less prone to external damage. Such packaging is generally done in a multi layered form to impart strength and durability to the final package. The lamination is introduced into paper in the form of either Aluminum or Low-density polyethylene (LDPE), or LDPE and Plastics of different family such as Polyester or Bi-Axially Oriented Polypropylene (BOPP) or Cast Polypropylene (CPP). Paper-based multi layered packages today enjoy tremendous popularity to pack FMCG products, food and beverages. One of the outcomes of using such packages, and the one which is generally left ignored, is the amount of waste that is generated once the package is opened and the content therein consumed. The empty/used packages, being non recyclable, due to the lamination, add to the bulk of community waste and lie neglected at dumping grounds thus causing an irreversible damage to the Earth and Environment.
Methods to fight this menace and recover the laminated component have relied mostly on recovering the paper component of the laminated packaging waste.
Recovery of paper is essential since for most of the packages paper form the largest (about 90-95%) bulk of the entire package weight. Any technique to recover the paper component would render the entire process not only highly profitable but would be environment friendly as well. The major concern with recovering paper, however, is the difficulty in saving it in any form and frame because of its delicate physique and sensitivity to any chemical, including water.
U.S. Pat. No. 4,188,259 teaches a method for recovering cellulosic fibres from thermoplastic-fibreboard laminates. The said method relies on an alternate high-low temperature and pressure treatment to separate the thermoplastic fragments from the cellulosic fibres. The method is restrictive in the manner that it only recovers the cellulosic fibre and not the thermoplastic fragments.
U.S. Pat. No. 4,168,199 discloses a method for recovering cellulosic fibres from laminated material having a cellulosic fibre layer and a metallic foil layer by a varying pressure treatment. The method also recovers the metal foil component.
Pyrolysis or chemical decomposition of condensed organic substances by heating has also been attempted as a delamination method. Ahmet Korkmaz et al in Waste Management (Volume 29, Issue 11, November 2009, Pages 2836-2841) discuss the use of pyrolysis to separate the constituents of a Tetra Pak package. The commercial value of such recovered constituents is, though, doubted.
Burning of the laminated package waste is also prevalent to recover the non-paper metal component and particularly the foil component. This method not only pollutes the environment but also wastes the bulk of the packaging material, i.e. paper, which is permanently lost as a result of burning.
Clearly, the prior art does not teach any method to individually separate all the constituents of a paper/cardboard-based laminated packaging waste. The methods of the prior art have been unsuccessful to recover all the constituents of a laminated package waste simultaneously and in a reusable form.
It is thus necessary to develop a method to delaminate paper-based multilayered packaging waste to recover the different constituents simultaneously. Such a method should additionally be able to recover the constituents in a manner that they are rendered useful for further processing or used/sold as such. The method should also be equally effective on cardboard based multi layered laminated packaging waste.